A plurality of rolling balls interposed between two surfaces is frequently used as an antifriction thrust bearing to enable relative orbital motion of the structures comprising each surface. The balls transmit the axial or thrust load from one surface to the other, while the rolling action of the balls allow substantially frictionless radial or orbital movement of one surface with respect to the other. Such bearings are particularly useful in machines undergoing an axial thrust while moving in an orbital motion, such as the scroll plates in a scroll compressor. When the ball bearings are constrained to roll within circular pockets, they can maintain a fixed angular relationship between the orbiting plates or between an orbiting plate and a frame. An example of this is disclosed in U.S. Pat. No. 4,468,181.
As an improvement over rolling balls in the scroll machine thrust bearing application, U.S. Pat. No. 4,259,043 discloses cylindrical rollers for providing a line versus a point contact for greater load carrying capacity per roller. This requires two sets of rollers separately disposed in two planes which are parallel to the moving surfaces. Aligning the rotational axis of the rollers in one plane perpendicular to those in the other plane enables two-dimensional movement of the surfaces in any direction parallel to the surfaces. With the rollers being disposed in two planes, however, an additional pair of bearing races are required, which increases the complexity and cost of the bearing.
Therefore, it is an object of this invention to provide an antifriction thrust bearing for orbital motion, wherein the rollers are disposed in one plane and the thrust is supported by a plurality of rolling line contacts.
Another object is to provide an antifriction thrust bearing that requires fewer rollers than if spherical or cylindrical rollers were used.
Another object is to provide a roller for an orbital motion thrust bearing, wherein said roller comprises two opposing cones which are coaxially aligned and joined at their base.
Another object is to provide an opposing cone roller thrust bearing for use between two parallel surfaces that allow their relative orbital motion but prevents rotational motion of the surfaces relative to each other, maintaining their fixed angular relationship.
These and other objects will be apparent from the attached drawings and the description of the preferred embodiments that follow below.